An integrated gas feeder used for a semiconductor manufacturing device or the like is generally configured such that, as shown in FIG. 12, using blocks 54 to 58 provided with a gas channel, two-way of/off valves 51A and 51B, three-way of/off valves 52A and 52B, a flow controller 53, and the like are connected in series to form one gas supply line, and a plurality of such gas supply lines are arranged in parallel and fixed to blocks 55 and 59 (JP-A-5-172265, etc.).
In addition, as the flow controller 53, a thermal mass flow controller or a pressure type flow controller is used, and the inside of each flow controller 53 is provided a flow control valve and a control circuit device thereof. Further, as the flow control valve, a piezoelectric-element-driven metal diaphragm control valve 53a is often used. The valve is configured such that the valve opening is automatically controlled to adjust the fluid flow as desired (JP-A-8-338546, etc.).
FIG. 13 shows an example of the flow control valve, that is, a normal-close piezoelectric-element-driven metal diaphragm control valve, which is often used for a flow controller in an integrated gas feeder, for example. The metal diaphragm control valve is composed of a valve main body 1 having a hole 1a in the upper surface thereof, a metal diaphragm valve element 2, a diaphragm presser 3, a pressing adapter 4, a piezoelectric element support cylinder 23 inserted vertically into the hole 1a, a disc spring 18 provided on the bottom wall of the support cylinder 23, a split base 27 inserted and attached into a lower part of the support cylinder 23, a lower cradle 9 provided in the support cylinder 23, a fixing guide 24 for the support cylinder 23, a piezoelectric element 10 provided in the support cylinder 23, and the like (JP-A-2003-120832).
In addition, FIG. 14 shows an example of a flow control valve configured such that a pressurizing spring 28 is provided between a piezoelectric element support cylinder 23 and a lower cradle 9 provided in the support cylinder 23, and the compressive force constantly applied to the piezoelectric element 10 is suitably adjusted to relax the tension caused upon the contraction of the piezoelectric element 10, thereby preventing the piezoelectric element 10 from breakage (Japanese Patent No. 4933936).
In the piezoelectric-element-driven metal diaphragm control valve of FIG. 13 or FIG. 14, in the steady state, the piezoelectric element support cylinder 23 is pressed downward by the elastic force of the disc spring 18, and the metal diaphragm valve element 2 is butted against a valve seat by the diaphragm presser 3. Thus, the valve is closed.
Then, when a voltage (control signal) is applied to the piezoelectric element 10, the piezoelectric element 10 extends, whereby the support cylinder 23 is pushed upward. Thus, the valve is opened. The reason for this is as follows. Because the lower end surface of the piezoelectric element 10 is supported on the split base 27 via a ball 8a and the lower cradle 9, as a result of the extension of the piezoelectric element 10, the support cylinder 23 whose upper end portion is fixed to an upper part of the piezoelectric element 10 is pushed upward against the elastic force of the disc spring 18, whereby the metal diaphragm valve element 2 that has been pressed is restored to the original state by its elasticity and separated from the valve seat.
The piezoelectric-element-driven metal diaphragm control valves shown in FIG. 13 and FIG. 14, etc., are advantageous in terms of responsiveness and flow controllability. However, because of the configuration in which halved split base segments 27a each provided with a flange are inserted inward from both sides of a piezoelectric element support cylinder 23 to form a split base 27, and a piezoelectric element 10 is supported on the upper surface thereof via a ball 8a and a lower cradle 9, the support mechanism for the piezoelectric element 10 is inevitably complicated, which inevitably makes control valve assembly difficult, resulting in the problem that it is difficult to achieve production cost reduction.
In addition, because of the configuration in which a flanged split base 27 is used, and the flanged split base 27 is fixed to a valve main body 1 by a fixing guide 24 for the support cylinder 23, the outer dimension of the fixing guide 24 naturally increases, resulting in the problem that it is difficult to achieve sufficient reduction of the control valve size.
Further, the integrated gas feeder shown in FIG. 12 is highly effective in that because a fixing bolt is removable from above, it is easy to exchange the control instruments forming each gas supply line, and it is also relatively easy to add more gas supply lines, etc.
However, when the number of gas supply lines required increases, the length dimension L of the integrated gas feeder naturally increases, resulting in an increase in the size of the integrated gas feeder.
The reason for this is as follows. Because of the structure of the flow control valve, there is a certain limit on the length dimension (thickness dimension) Lo of the flow controller 53, and, in either case of a thermal flow controller (mass flow controller) or a pressure type flow controller, a thickness dimension Lo of 20 to 25 mm or more is required.
In particular, in recent years, in an integrated gas feeder for a semiconductor manufacturing device, it has been strongly demanded to increase the number of gas supply lines required, that is, to increase the variety of supplied gases, and there has been a practical demand for an integrated gas feeder capable of supplying a dozen or more kinds of gasses.
In addition, at the same time, significant downsizing of an integrated gas feeder has also been strongly demanded. For example, in a one-chamber multi-process system, it has been practically demanded to fit an integrated gas feeder having 16 kinds of gas supply lines in a volume space of a 350 mm in width W, 250 mm in length L, and 250 mm in height H or smaller.